Fastening means for separable parts



March 3, 1931. I H. A. cALDERwood 1,795,107

FASTENING MEANS FOR SEPARA'BLEPARTS Filed Feb. V1, 1929 FIGS. F|6.4. Has. Fl6.6.

awueutoz 7,4 4 c'ummw as mwm W' IEDLS Patented Mar. 3, 1931 PATENT OFFICE 'VIHUGH A. onnnnawoon, tor rr'r'rsnunen, PENNSYLVANIA, ASSIGNOR TO NATIONAL ELECTRIC"PBODUC'ISQCORIOBATIONL on NEW YORK, N. Y., A eonrona'rron or DELAWARE rasrnninemnaivs non SLEPARABLE reams Application filed February '1, 1929. Serial No. 336,809.

' ln' electricalwiring practice where conduits and outletb oxes and'the like are'employed occasion frequentlyarises where various separate parts are held; together by small f 'screws. The parts and assemblies are trequently of such character that it is necessary that they beassembled and disassembled several times befo-re'theinstallation iscomplete. This-means that the attachingfscrews must "be removed and replaced, which operation is not only troublesome and annoyingbecause of the frequent inaccessibility of the screws but in addition these'screws frequently becomelost and have to be replaced with others which may notbe available. The annoyance and difficulty is especially encountered with ceiling outlet boxes provided with separate" fixture studs which are screwed to the boxes' With such constructions the screws are rather inaccessible. and in replacing them the act of replacing is troublesome and also there i is great possibility and even a probability of loosing the screws when they are being removed or replaced.

The present invention has for one of its objects the provision of a novel form of fastening means for uniting separate parts by" which the annoyance and difiiculty of re- 'moving and replacing screws may be minim ized and in which the insertion and engage- A further object of the present invention.

resides inthe provision ofa novel form of screw fastening means for securing together separable parts such as an outlet box and a fixture stud and in which the screws may be left in assembled relation and engaging the the other cooperating part, such as an outlet box, when it is desired to disassemble the parts. y

A further objectof the present invention resides in the provision of a construction employing anexpanding meanswhich is adapted to be expanded by the screw to clamp the same firmly to a cooperating part.

A further object of the present invention resides in the provision of a removable fastening construction employing an expanding member and a screw with a wedging portion and provided with a head of reduced size, all of which parts are adapted to be passed directly through a cooperating opening in one member, such as an outlet box, when it is desired todisassemble-the separable parts.

" Further and other objects of the present invention will be hereinafter set forth in the accompanyingspecification and claims and .shown in the drawings which by way of illustration show invention.

In the-drawings: Figure 1 is a bottom view of an outlet box incorporating my improved fastening means;

preferred embodiments of the Fig. 2 is an enlarged sectional view taken on line 2-2 of Fig. 1; i i V l 3 Figs, 3 to 6 inclusive, show different forms ef-expanding members. i

In more deta hl have shown my improved fastening means as used to fasten together an outlet box 10 "and a fixture stud 11. The latter part comprises alug or car 12 which dips through an opening 13 in the outlet box and extends under the bottom of the top plate of the box. The part also comprises an extended portion let disposed over the top of the outlet box which is provided with a threaded opening to receive a fastening screw. Suchpart 1 1 and the screw threads are relatively inaccessible being covered from below by the outlet box which is provided with an opening 15. In lieu of using a screw with a large head so as to extend over the marginal edges of opening 15 as heretofore, a screw such as '16 is provided having a screwslottedhead ofreduced size so that it can pass through the opening 15. After the, screw 16 isthreaded into and assembled j into part 14 of the fixture stud, the u per end 'oflthescrew is upset as shown at 1' 7 subsequently it is difiicult or impossible to so that unscrew 16 completely out of 14. VVithinthe opening. I provide an expansionmember 18 which'is adapted tobe expanded tightly intocontact' with the edges of opening lf) upon tightening up screw '16. To provide for such expansion the screw 16 is provided with .wedging surfaces 19. The expansion member 18.1nay be made in various ways. It maycomprise a slotted collar-like mem ber such as shown at'18 in Fig. 3. If desired,

it may be a plain unslotted collar of com- 7 paratively soft material asshown-at 18bin Fig. 4c, or the slot may extend substantiallyhalf way as shown at 180 in Fig. 5. Also an expansionmember may be provided by utilizing smallsection of spring as shown v at 18d in Fig. 6;

'Whenin use, and when it is desired to disassemble. the box and fixture stud the screw stud 16 is backed off. The expansion member 18 can then contract and it and the head ofthe screw can be passed upwardly I through the opening '15. 3T0 assemble the parts and. secure them together the head of the screw is passed down through the opening and the stud 16 then tightened. Thisspreads or expands the expansion member I and causes it to tightly grip the box 10. By

this construction-thescrew or stud 16 is al- Intestimony: whereof I the underlying part, said means and screw being both adapted to pass through theaperture in the underlying part upon backing off of the screw and while it is still secured in the overlying part. I

2. A fixture stud and box assemblage and fastening means therefor to permit the connection and disconnnection of the'fixture stud and box with the box in situ and concealing and rendering inaccessible overlying parts of the fixture stud said box: having an aperture therein in its upper wall; said'fixture stud having a part which overlies the said wall provided with a threaded aperture,

a screw stud threaded in said threaded aper.

ture and having a head portion 'adaptedto pass through the aperture in upper-wall of the box, saidheadfhaving a screw slot therein and a wedging portion on its head,fand

means disposed in the aperture of the upper wall portion of the box which is' displaced into clamping. relation, with the walls of the aperture by the wed'gingf portion 'of' the screw upon tightening of the screw for securing-the fixture stud to the box, said screw and means being adapted topass through the off of the signaturel ways-maintained in assembled relation to the p L fixture stud and it is never. necessary to completelyremove the screw to disassemble the parts accordingly the bother and-nuisance of-trying to engage therelatively inaccessible screw threads is obviated and also there. is

' no possibility of losing thescrews.

What Iclaimisr V 1. A fastening means for'separable parts which parts include one inaccessible part overlying another underlying part which is 1 accessible from. below, said latter partbeing provided with an. aperture, said fastening means .comprisinga screw having a threaded.

engagement with the overlying inaccessible part andadapted to be screwed inlor out to a p I slight extentwith respect tothe same to secure the parts together or permit their dis- "connection, said screw having a head adapted to pass clearly through the'aperture a 1n the underlying part and having a. screw slot in the head which is accessible from be- I low the underlying part" to permit in or out I turningofthescrew, said screw head having a tapered wedglng portion and means co- --operating therewith and dispose d in the aperture of the underlying part, which means is adapted to beclamped by the wedgmg portion of the screw head into clamping relation with the walls of the aperture in 

